WHEN FRENCH mathematician Pierre de Fermat died in 1655, he had not written down the proof of a theorem, "which this margin (of my notebook) is too small to contain". More than three centuries later, Andrew Wiles of Princeton University claims to have proved Fermat's Last Theorem.

The theorem states that in an equation containing whole numbers, if x raised to the power n, plus y raised to the power n, equals z raised to the power n (xn + yn = zn), then the value of n cannot be greater than 2.

Fermat proved his assertion when n is equal to 4 and one proof is known to work for values of n upto 4,000,000. None of this, however, constituted persuasive proof because the possible values of n are infinite.

Wiles claims to have provided absolute proof. There are only half-a-dozen people capable of understanding Wiles' work. And, given the complexity of the 1,000-page proof, it could take several months to be certain that every detail Wiles relied on is correct.